Generally, many public facilities such as banks, department stores and prisons are guarded by patrolling cars at intervals of certain periods. However, such a guarding method is not efficient enough to prevent or detect crimes and other accidents.
Such a guarding method depends on human efforts and, therefore, the carelessness and mistakes of the patrolling persons can fail to notice a problem. Thus, an intruder who well knows the situation of the watched area can escape the detection of the patrolling persons. Consequently, many accidents are still generated and the loss of property occurs.
In order to overcome the above described problems of the human watch method, a recently developed new guarding and security system includes a closed circuit provided with a camera or the like for detecting objects plus a monitor capable of displaying the watched area to allow quick warning and action following an accident such as a fire, or an intrusion.
However, such a guarding system requires a large number of cameras to be installed at critical places in the watched area to the need for such a large number of cameras increases the cost of the guarding system. Cost is also increased by, expensive recording apparatus and a plurality of video tapes for recording the data photographed by the watching cameras.